Finding affordable PCIe options for sound aficionados.

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For years, we've trumpeted the benefits of discrete sound cards. They simply sound better than the typical integrated audio on motherboards, especially for those with discerning ears and halfway-decent speakers or headphones. Good sound cards tend to last through multiple upgrade cycles, too. They're amazingly inexpensive considering the expected lifespan. Indeed, the two we'll be putting under the microscope today—Asus' Xonar DGX and DSX—sell for less than $50.

If the names look familiar, that's because the cards are the PCI Express versions of the Xonar DG and DS. Those older models have PCI interfaces, like an awful lot of other sound cards, and PCI slots are quickly disappearing from modern motherboards. The Xonar DGX and DSX drop into any PCIe x1 slot, and those should be with us for a good, long time.

Each card has a unique character. The DGX courts headphone users with a dedicated amplifier and Dolby Headphone surround-sound virtualization. Meanwhile, the DSX offers home-theater users a replaceable OPAMP, support for more output channels, and the ability to encode multichannel digital bitstreams in real-time.

How do the two compare, and more importantly, how good do they sound? We've conducted a mix of performance, signal quality, and blind listening tests to find out. We've also thrown in our favorite mid-range sound card, the Xonar DX, and a motherboard with Realtek's latest audio codec. This should be interesting.

The Tech Report

Before we dig into the Xonars, it's worth taking a moment to expand on why sound cards tend to last so long. To be frank, the market for them has largely stagnated.

Games used to drive the demand for hardware-accelerated audio, but that feature has all but disappeared from recent titles. Creative's EAX positional audio scheme died years ago. OpenAL was supposed to be a replacement of sorts, but Creative's list of games with OpenAL audio hasn't been updated since 2008. Blue Ripple Sound's Rapture3D positional audio software is used by some Codemasters games, and it's been made to work with a handful of OpenAL titles. However, Blue Ripple Sound is quite explicit about the fact that its algorithms run on the CPU.

The fact is today's multi-core processors have an abundance of horsepower. Crunching numbers for positional audio shouldn't be a challenge. These days, developers typically handle positional audio processing in software. Some, like Battlefield 3 maker DICE, even offer their own virtualization voodoo.

Perhaps because the need for hardware acceleration has waned, the flow of new audio processors has slowed to a trickle. We've had plenty of output channels and real-time encoding options for quite some time, leaving few reasons for fresh silicon.

The older audio processors that dominate the market are designed for the PCI interface, which is quickly falling out of favor among motherboard makers. Intel dropped PCI support from its consumer desktop platforms years ago, forcing board makers to employ third-party silicon if they want to offer PCI slots. Most still do, but it probably won't be long before the majority of new boards are PCIe-only.

Since the C-Media audio processors used in the Xonar line lack native PCIe support, Asus has taken to using bridge chips to link up with the newer interface. The DGX and DSX both feature PLX's PEX8112 bridge chip, just like the other PCIe members of the ever-growing Xonar family. Bridged solutions aren't quite as slick as native ones, of course, but we've yet to see any issues related to Asus' use of the PLX chips.

In the picture above, you can see the bridge chip next to C-Media's Oxygen HD CMI8786 audio processor on the Xonar DGX. That's the same C-Media chip as on the older DG model. Likewise, the DSX features the same Asus AV66 audio processor as the Xonar DS. Though Asus' name is silkscreened on the surface, the AV66 is actually a C-Media CMI8788. Asus tells us the AV66, AV100, and AV200 processors featured on its Xonar cards are all variants of the CMI8788 with different software packages.

We're at a loss as to why Asus doesn't have its own name branded across the CMI8786. That chip is a custom order just for the Xonar DG and DGX. The CMI8786 is really just a cut-down version of the CMI8788. Both chips can handle 24-bit audio, but the CMI8788 does so at sampling rates up to 192kHz, while the CMI8786 tops out at 96kHz.

As the model numbers suggest, the CMI8788 can feed eight output channels, while the CMI8786 is capped at six. Translation: the Xonar DSX can power 7.1-speaker home theaters, while the DGX is limited to 5.1-speaker setups.

Asus uses a different mix of complementary digital-to-analog and analog-to-digital conversion silicon on each card. The DSX pairs a six-channel Wolfson DAC with a stereo codec from the same company. Cirrus logic supplies the conversion hardware for the DGX, which uses a similar DAC-and-codec combo. Incidentally, all of the DAC and codec chips offer 24 bits of resolution at 192kHz sampling rates. The Xonar DGX's 96kHz limitation comes from its audio processor alone.

The published signal-to-noise ratios of each card give us a general sense of their overall signal quality. Looks like the Xonar DGX might be the more balanced of the two; it has a 105-decibel output SNR and a 103-dB input SNR. The DSX has higher output SNR, at 107 dB, but its 100 dB input SNR is a little low.

The Xonar DGX is the less expensive of the two cards, but by less than the cost of a super-sized McDonald's combo. Deciding between the two may be more a factor of whether you intend to hook up the card to a fancy home-theater receiver or run it through a headset or headphones. We'll explore the features tailored to each setup as we take a closer look at each card.

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76 Reader Comments

I am using a Xonar DG card in my current system - the predecessor to the DGX mentioned in this article. It is a great card with lots of great features, however one thing that has consistently let it down is Asus' poor driver support. I installed the drivers that came with the card and everytime I play an mp3 track - I randomly get pops/skips. This is something that Asus were aware about from their support forums. I often have to quickly skip back on the player to see if the skip was due to bad encoding on my part since I rip the tracks from CD. It never is however. The pops and skips just randomly happen. Since v1.0 of the drivers I have installed 3 more driver updates that claim to fix this issue but they never did. Currently the latest driver is from October 2011 and given that it's August 2012 now - makes me realise that they probably wont do any anymore updates for this card. This means I have to live with the random pops/skips, which is hardly pleasing. Its a great card otherwise, just wish they would keep updating/improving the drivers.

I can't say I really understand all the graphs...but what I took away was that base sound quality is no better, and sometimes worse, than onboard. So...I still don't understand the point of a discreet sound card anymore.

For me anyway I use a discreet card for gaming. My headset plugs into the onboard sound for Ventrilo, and my speakers into the card. So I can actually hear what people are saying in Ventrilo, and have the game sound on.

Geoff, you didn't mention this in your article, but setting the sampling rate and bit depth in Windows 7 / 8 can make a significant difference in the playback quality for different audio codecs and hardware.

In my own (2-channel music audiophile) testing, I have discovered that settings anywhere from 16-bit/48kz all the way to 24-bit/96kz can sound "best" depending on the hardware in use. (In Windows Vista, 7, or 8, sound from your PC will almost always sound better upsampled to at least 48kz than when using the default 16-bit/44.1 setting.)

These differences are also audible using S/PDIF. Upsampling in Windows prior to sending a digital signal to a DAC is usually better than letting the DAC handle it natively, in my testing. (I've never been satisfied with the analog outputs of any card or motherboard I've tried, and so typically take digital feeds off of the PC, either via S/PDIF or USB.)

I have had a DSX card for about 8 months now and I absolutely love it. Despite it not being "built for headphones" like the DGX, I have a set of 5.1 surround sound multiple speaker headphones with their own amp, so it works quite well in this circumstance. I would definitely recommend this brand to anyone, and the sound performance is quite distinguishable from most on board sound cards

Edit: I realise its probably not a DSX card I have, probably a DS, but it does have a regular PCI slot, not PCIE, either way, a great card and I'm sure the new iteration is only better

The article have a better layout over TechReport : they have a table of content, from which you can switch directly to the section you're looking for, instead of having to browse through pages only identified by page numbers.

If you're a subscriber the article is on a single page, which IMHO is superiour to anything else.

My primary takeaway from this article is that the author needs to learn about confirmation bias.

Just about the only thing of real value seemed to be the frequency plots, which showed me that in the range of human hearing (20-20kHz) onboard is objectively just as good as discrete. If the evil queen ever turns me into a dog, though, I'll be sure to come back and see which card would be better for ears sensitive into the 45kHz range.

I assume the output distortion etc. tests were mainly limited by the cards' DACs - as I'm currently using onboard audio with S/PDIF stereo output, can anyone tell me if I'd see any difference at all going to a discrete sound card?

My receiver is brand new, but it sucks so this doesn't work. I mean, it does work in theory, it supports multichannel PCM out. But for whatever reason switching between a PCM output and any encoded stream (like Dolby Digital) kills the output until I reboot.

Sucks because I use Windows Media Center for my DVR needs, which (unlike XBMC and other players) doesn't have any option to decode the stream to the 5.1 "analog" (HDMI PCM) output. It always switches to SPDIF output, killing the audio.

So for now I'm still stuck using my motherboard's optical out (luckily XBMC will re-encode on the fly all the videos that are in 6-channel AAC and such).

EDIT: Actually, this could easily be a driver issue as well, and have nothing to do with my receiver.

It does look like driver issue on your PC. But if SPDIF works then why not just stick with that? Is there any advantage in using HDMI? Are you also using it for video? Sorry, I've never used HDMI, only DVI and SPDIF on all my PCs.

I assume the output distortion etc. tests were mainly limited by the cards' DACs - as I'm currently using onboard audio with S/PDIF stereo output, can anyone tell me if I'd see any difference at all going to a discrete sound card?

Zero, unless you'd benefit from on-the-fly DTS (or Dolby) encoding.

EDIT: What the guy below said. It's not touching those circuits, the bits are traveling all the way out of the case.

I assume the output distortion etc. tests were mainly limited by the cards' DACs - as I'm currently using onboard audio with S/PDIF stereo output, can anyone tell me if I'd see any difference at all going to a discrete sound card?

It's a pass-through device, so it never hits those circuits. I use to buy soundcards up until they got the onboard drivers working.

My receiver is brand new, but it sucks so this doesn't work. I mean, it does work in theory, it supports multichannel PCM out. But for whatever reason switching between a PCM output and any encoded stream (like Dolby Digital) kills the output until I reboot.

Sucks because I use Windows Media Center for my DVR needs, which (unlike XBMC and other players) doesn't have any option to decode the stream to the 5.1 "analog" (HDMI PCM) output. It always switches to SPDIF output, killing the audio.

So for now I'm still stuck using my motherboard's optical out (luckily XBMC will re-encode on the fly all the videos that are in 6-channel AAC and such).

EDIT: Actually, this could easily be a driver issue as well, and have nothing to do with my receiver.

It does look like driver issue on your PC. But if SPDIF works then why not just stick with that? Is there any advantage in using HDMI? Are you also using it for video? Sorry, I've never used HDMI, only DVI and SPDIF on all my PCs.

SPDIF works, but 5.1 PCM is (marginally) higher quality than DTS/DD. That's not my real concern, though, I don't notice much difference. Of greater concern is that my my reciever has only one optical input, and I have two optical devices (counting the HTPC), meaning I have a manual switcher I have to click every time I switch between them. Thankfully this isn't often!

Also, this means no 5.1 in games (I play a couple on the HTPC from time to time), since optical only does stereo PCM.

It's awesome! We love it, we love TR, and we know that no one will be harmed by the publication of this review. None of our readers, anyway

But 'tis the season of building new PCs. At least, I know a bunch of people doing that right now. Myself included.

In the meantime, I'd add TR to your RSS.

I didn't quite know the site before and the article was interesting, though I actually can't shake of the feeling of having gone back 10 years with a review of low-end discrete sound cards . Anyway, if one doesn't send the sound through HDMI or SPDIF to some receiver hooked up with actual hifi speakers (at 1000 eurodollars the good amp/2 speakers combination, that's arguably a common case), it remains an interesting article to read. Especially since the article almost unintentionally highlight the fact that onboard audio isn't that bad.

Now, a terrific question has arisen: why on Earth doesn't Asus use its Xonar chips, amps and circuitry directly on their motherboards? I've already seen some of their [url="http://www.asus.com/Motherboards/Intel_Socket_1155/Maximus_V_GENE/"]high-end boards[/url] using some kind of Creative X-fi chips, so why it is they don't use their own solution in their high-end boards?

Sounds like a non-review and non-recommendation. There are thousands of recording that you can recommend different audio products for just because of the deficiencies with they recordings. How about linear performance under controlled conditions? What happens when I bring out an old pair of ESLs and just absorb?

Man oh man...I remember the days when the biggest factor preventing me from moving from Amiga to PC was the lack of inbuilt audio, and even the vaunted Sound Blaster was a poor replacement although its ability to record and play back digital audio made it alot more acceptable then the Ad Lib or Roland alternatives.

I remember lusting over (and then buying) a Gravis Ultrasound, the first consumer grade Wavetable synth card where the more RAM you stuck on it the better it sounded.

And then came the day that a/ ALL music became digital and both FM and wave synthesis were passe. Not only that, processor power grew to the point that wavetable synth in software was viable if you REALLY wanted it.

Ever since the days of the AC97 integrated onboard sound chips were standardized, PC audio cards just kind of lost their mojo.

Its refreshing to read an article like this to bring back some of the love. Thank you!

The text: "They simply sound better than the typical integrated audio on motherboards, especially for those with discerning ears and halfway-decent speakers or headphones."

The actual measurements: Onboard audio sounds better, uses less power and is more compatible across the board.

Like I said before, the actual measurements aren't done under the same conditions as the listening test, and are basically irrelevant unless you're using an external amplifier. So its entirely possible there is a meaningful difference.

Of course, since we have no idea which is the case, I guess you could find this review pretty funny

I'm a big proponent of using SPDIF-linked external DAC/preamp/headphone amps, at least in the 2-channel realm. Trying to get a clean analog signal out of a PC expansion card is kind of an exercise in futility, or overly cost-prohibitive. If I'm doing 5.1, say, on my HTPC, I just pipe it out to my home theater receiver/preamp. I guess these cards could be useful to people trying to do 5.1 on their desktop PC for gaming, but nice headphones seems oh so much more practical for that.

I have been using a Roland/Edirol/Cakewalk ua-25 ex for a few years now. Since last year I use it together with a pair of Genelec 8040. This setup is as close to flawless and problemfree as I would ever care to have, and on top of that it's just three parts and three cables (+ two mains power to the speakers, amps integrated). Having external studio-oriented stuff enables me balanced cabling (with earth lifting) for hiss and noice free playback (I didn't by studio stuff to do sound production, i just got a bit fed up with the hifi-industry). Having the ua-25 on my desc gives me a volume knob on the desc as well . My point being that external sound cards has some purely practical features, even if there are integrated card that sound just as good (m-audio delta 24/96, anyone?).

I have had nice sounding setups in the past, but the best one before this was to much stuff; dac, filters, amplifiers, preamp, sub and main speakers. Even as the genelecs cost ~1500 euro for a pair, it's not that expensive as the only things needed to complete the setup is two balanced cables and a usb sound card.

Multi-channel audio is such a pain in the ass on computers, and I blame Dobly....If the stream is already encoded, as is the case with DVD or Blueray, the can pass the stream to the digital output, but if the stream needs to be constructed realtime, as it would in a game, you need an encoding license from Dobly, and that is expensive.

A few people have asked if they support analog and s/pdif output at the same time. Generally speaking, if you are not using Dolby Live the answer is yes, you can have unique audio to both devices. With many cards (at least every one I've encountered), when you enable Dolby Live, it disables the ability to have unique audio. The s/pdif becomes a DTS mix of the analog.

If you want the same thing coming out of both ends, this does what you need (and I'm assuming most people fit into the category of only having one system hooked up at a time). If you want two seperate surround mixes coming out of each output, you're out of luck.

After reading this article though, it may be time to upgrade my sound card...I can swing $50 for the DSX...funny how only $9 seperates the "low end" card from the "high end"; used to be more like $50-$100!

That's because it's not a high end card. There's still $150-200 high end sound cards if you want to pay for them.

Onboard audio with digital output to a receiver is fine. Bits are bits.

This article is stupid. The author is either clueless, or lying.

If you play some games with a soundcard, the bits are different. Not every onboard audio can mix DTS on the fly, I know mine did not. Very few games output in DTS (there are a few). If youre using digital out, sound cards become the easiest way to actually get surround in games due to Dolby Live. If you're only watching blu rays and movies, then it becomes less relevant as the audio on the disc is able to just be passed through and you get the surround you want.

Onboard audio with digital output to a receiver is fine. Bits are bits.

This article is stupid. The author is either clueless, or lying.

If you play some games with a soundcard, the bits are different. Not every onboard audio can mix DTS on the fly, I know mine did not. Very few games output in DTS (there are a few). If youre using digital out, sound cards become the easiest way to actually get surround in games due to Dolby Live. If you're only watching blu rays and movies, then it becomes less relevant as the audio on the disc is able to just be passed through and you get the surround you want.

I don't get your point. Much if not almost every motherboard have at least one optical SP/DIF output, so where is the need for a discrete audio card if you plan to use digital output?

Onboard audio with digital output to a receiver is fine. Bits are bits.

This article is stupid. The author is either clueless, or lying.

If you play some games with a soundcard, the bits are different. Not every onboard audio can mix DTS on the fly, I know mine did not. Very few games output in DTS (there are a few). If youre using digital out, sound cards become the easiest way to actually get surround in games due to Dolby Live. If you're only watching blu rays and movies, then it becomes less relevant as the audio on the disc is able to just be passed through and you get the surround you want.

I don't get your point. Much if not almost every motherboard have at least one optical SP/DIF output, so where is the need for a discrete audio card if you plan to use digital output?

You're right that the port is there... unfortunately in most cases it only puts out stereo unless the source passes through DTS thats already been mixed in 5.1. You can set the receiver to try to simulate surround, but converting 2.1 -> surround isn't so hot for positional audio.

"SPDIF does not have the bandwith to send uncompressed 5.1 audio, hence, why only Dolby and DTS can give 5.1 audio over SPDIF. Unless you have a realtime encoder, probably from a soundcard, you will not be able to get 5.1 audio unless the track you are trying to send is already in Dolby/DTS format. "from this http://www.tomshardware.com/forum/30214 ... dif-output

He hit the nail on the head. I know that my onboard sound would not encode dts real time. I can't speak for all of them out there, but there are at least some that are incapable of encoding 5.1 dts on the fly.

Unless the listening test was falsely claimed to be "blind" instead of "double blind" I'd say it is worthless. It eliminates some bias, but not enough to be really worthwhile. A good setup for that is btw harder than one would imagine...

Another thing I missed, given the length of the article, were some measurements about the mic ins. They are the reason I use discreet soundcards. Most onboard and especially laptop mic ins are so plain terrible that even the cheapest headsets you get with 50$ cell phones would be limited by that. [exaggeration]And in addition to that it would have been interesting to hear what flavors of phantom power those cards support and how well within spec they do so. (I e.g. use a HSP 2 and those need 12V. No, I am not a lunatic but had a chance to get one too cheap to consider not buying it.)

Another interesting thing would have been a test of the headphone out (with varying load) to see how clean that one is and how much better the headphone amp does really.

My receiver is brand new, but it sucks so this doesn't work. I mean, it does work in theory, it supports multichannel PCM out. But for whatever reason switching between a PCM output and any encoded stream (like Dolby Digital) kills the output until I reboot.

Sucks because I use Windows Media Center for my DVR needs, which (unlike XBMC and other players) doesn't have any option to decode the stream to the 5.1 "analog" (HDMI PCM) output. It always switches to SPDIF output, killing the audio.

So for now I'm still stuck using my motherboard's optical out (luckily XBMC will re-encode on the fly all the videos that are in 6-channel AAC and such).

EDIT: Actually, this could easily be a driver issue as well, and have nothing to do with my receiver.

Could also be an EDID issue. If you feel like troubleshooting, head over to AVSforums and look around.

Onboard audio with digital output to a receiver is fine. Bits are bits.

This article is stupid. The author is either clueless, or lying.

If you play some games with a soundcard, the bits are different. Not every onboard audio can mix DTS on the fly, I know mine did not. Very few games output in DTS (there are a few). If youre using digital out, sound cards become the easiest way to actually get surround in games due to Dolby Live. If you're only watching blu rays and movies, then it becomes less relevant as the audio on the disc is able to just be passed through and you get the surround you want.

I don't get your point. Much if not almost every motherboard have at least one optical SP/DIF output, so where is the need for a discrete audio card if you plan to use digital output?

Somebody else tried to answer, but I'll keep it a bit more simple:

You cannot get surround sound in 99% of games over the digital output on your motherboard. This requires either Dolby Digital Live or the DTS equivalent, which 99.9% of motherboards do not support. So that built-in optical is stereo-only for 99% of games.

In case nobody mentioned this, the PLX PEX8112 IC which you can see on both cards is a PCI-Express to PCI bridge which means those cards are not native PCI-Express (the DSP chip does not have native PCI-Express interface) and are thus crap to begin with. Think of it as fake PCI-Express.

Creative X-Fi Titanium PCI-Express series (no longer sold) and new Recon3D (which is not so good at least according to the specs) are native PCI-Express solutions and thus do not carry over any inherent PCI bus limitations.

Multi-channel audio is such a pain in the ass on computers, and I blame Dobly. If you want multichannel from a game, you have 2 options; mulit-channel analog output or Dolby Digital Live (DDL). Very few stereo receivers are supporting 5.1 or 7.1 analog in, and very few cards support DDL. I have a 6 year old turtle beach card that has DDL, so I can run a TOSLINK cable to my reciever and play games in 5.1. If it wasn't for DDL, I would be stuck with stereo.

HDMI has solved this problem on PCs - it can carry uncompressed multi-channel sound to your AV Receiver with no need for DDL or DTS encoding.Your limitations only apply to Optical/CoAx SPDIF connections (which don't have the bandwidth to carry more than two channels without compression, ie DD or DTS).

Also, I have to question some of the author's results. As other have mentioned, the subjective tests don't appear to match the objective ones very well. Further, he finds a 60 Hz spike in IM distortion... something tells me this might have been a grounding issue. Anyone who has played with subwoofer inputs in their home knows exactly what 60 Hz sounds like... it is the EM field created by your home wiring in the US.

I actually switched from using an unloved Hercules DJ console (never used as a mixing device) as an external sound card to my on-board when I got an i7 and Gigabyte motherboard. The sound quality was an exceptional amount better with the on-board sound. First time anything had beat the DJ console, and I had put it up against original Ensoniq 1370 AudioPCI, SB Live, and an SB Audigy. Annoyingly, my A/B testing showed Creative uses non-linear output on the Audigy towards excessive and muddy bass as well. Then again, Creative has sold audio cards with better rear than front DACs (Live series, possibly some Audigy's as well).

Still none of these things hold a candle to anything from M-Audio, which aren't even very expensive by comparison (no PCIe, so what?).

Frankly, leaving 1 PCI slot on a motherboard for legacy devices costs the motherboard and south bridge manufacturers very little and unlike the VESA & ISA interfaces of yore, plain jane PCI does not cause a performance impact to the CPU since it supports DMA. PCI to PCIe chips on the other hand visibly add a lot of latency and compatibility issues, which is just bad pool.

I do have to say, we're pretty much looking at is a middling review about products which ultimately remain without much interest or merit.

Audiophiles are going to man up, get at least an M-Audio Audiophile 4 in 4 out for $80 at the entry level (or the older 4 in 10 with all RCA connections around the same). Some gamers might buy into the free FPS from Creative's garbage offerings. Everyone else will be well served by on-board analog or S-PDIF / Toslink to their receiver.

Frankly, leaving 1 PCI slot on a motherboard for legacy devices costs the motherboard and south bridge manufacturers very little and unlike the VESA & ISA interfaces of yore, plain jane PCI does not cause a performance impact to the CPU since it supports DMA. PCI to PCIe chips on the other hand visibly add a lot of latency and compatibility issues, which is just bad pool.

Except ISA dropped PCI support in their chipsets probably half a decade ago; the PCI you see on Intel are all from bridge chips.

I am interested in similar articles; sound is an interesting and important theme for technological analyses.But since they rarely appear on ArsTechnica, it would make more sense had it had more cards compared.Unless more are planned for the future.

I used to test soundcards professionally- those crosstalk numbers are horrible- looks like you probably used a standard RCA or 1/8" stereo cable where the left and right channel wires are unshielded and glued/formed together. Get a 1/8" stereo to RCA splitter on each end and and run with separate RCA cables and you will likely see much improved crosstalk that actually reflects the capability of the card instead of the poor cable interconnects.